Testing Roblox games

Make code testable first

• Keep game rules in pure ModuleScripts (inputs → outputs, no services, no yields): damage formulas, inventory operations, shop pricing, state machines, serialization, validation. These are trivially testable.
• Services take their dependencies as parameters (dependency injection) so tests can pass fakes instead of real DataStores, remotes, or Players.

--!strict
-- ReplicatedStorage/Shared/Inventory.luau — pure logic, no Roblox services.
export type Inventory = { [string]: number }

local Inventory = {}